Stress-Inflammation Dysregulation and Biomarker Dynamics in Pediatric <em>Mycoplasma Pneumoniae</em> Pneumonia

Mycoplasma pneumoniae pneumonia (MPP) is a common pediatric infection frequently accompanied by systemic inflammation and psychological stress; however, its potential bidirectional relationship remains poorly defined. We retrospectively analyzed 120 hospitalized children aged 5-12 years using the Child Stress Questionnaire (CSQ), inflammatory mediators (CRP, IL-6), and three clinical biomarkers (LDH, D-dimer, MP-DNA load). Elevated LDH and D-dimer were significantly associated with higher CSQ scores (r = 0.67, p < 0.01) and more severe inflammatory responses. Children with prolonged illness (>7 days) and high MP-DNA load had markedly higher stress scores (mean 38 vs. 25, p < 0.01). LDH ≥ 450 U/L independently predicted extended hospitalization (OR = 2.1, 95% CI: 1.2-3.7), and ROC analysis demonstrated strong discriminative power for severe complications (AUC = 0.89, 95% CI: 0.83-0.95; sensitivity = 82%, specificity = 81%). These findings support a bidirectional link between psychological stress and immune dysregulation in pediatric MPP and highlight LDH and D-dimer as practical biomarkers for early identification of high-risk children.